The present disclosure relates to semiconductor device fabrication, and, more specifically, to methods of forming gate structures using selective metal deposition.
Photolithography is a commonly used technique in the manufacture of semiconductor devices. The process uses patterns to define regions on a substrate. More specifically, with photolithography, a photoresist layer may be formed on a substrate, such as a silicon wafer, and then the resist layer is covered with a mask containing a pattern. The mask is exposed to radiation, such as ultraviolet light (UV), which is transmitted through transparent areas of the mask to cause a chemical reaction in corresponding regions of the photoresist. In other words, in the course of processing integrated circuits and the like in semiconductor devices, a standard sequence may involve putting down a layer of material, depositing a layer of photoresist on the layer of material, patterning the photoresist by projecting a pattern on it, and developing the resist to produce a pattern of open areas that expose the material, with the other areas of the material still covered by the resist.
Complementary metal-oxide semiconductor (CMOS) devices typically employ at least one gate that is separated from a conducting channel (or channels) of the device by a gate dielectric material. Examples of such CMOS devices that employ a gate dielectric material include, but are not limited to, field effect transistors (FETs).